A. Field of the Invention
This invention relates to a surgical operation microscope, and particularly to an operation microscope including an illuminating optical system for illuminating an eye through an objective lens and an observing optical system for observing the eye through the objective lens.
B. Description of the Prior Art
Heretofore, there have been proposed various kinds of surgical operation microscopes. One such example is illustrated in FIG. 11.
In FIG. 11, the symbolic numerals 1a, 1b denote oculars with which an inspector observes the anterior portion of an eye E, prisms 2a, 2b and imaging lenses 3a, 3b. The symbolic numerals 4a, 4b denote beam splitters. The beam splitter 4a is adapted to guide images of current information to the ocular 1a, and the beam splitter 4b is adapted to split a ray of light reflected by the cornea of the eye E and guide the same both to the ocular lens 1b and to a corneal configuration measuring device 11. The symbolic numerals 5a, 6a, 5b, and 6b denote variable lenses, 7 an objective lens and 8 a ring light source which also serves as a projected target mark. The numeral 9 denotes a display, L a relay lens, and 10 a mirror, respectively.
Data gathered by the corneal configuration measuring device 11 is displayed on the display 9, and the displayed data reaches the ocular 1a through the mirror 10, the beam splitter 4a, the imaging lens 3a and the prism 2a, so that it can be observed.
However, since a surgical operation microscope of the above-mentioned type uses the beam splitters 4a, 4b, light quantity seen through the oculars 1a and 1b is reduced. For that reason, the illuminating light source must be brighter. Under these conditions, it is difficult to protect a patient's eye.
Also, there is another type of a surgical operation microscope which leads a guid images of information on a display to the ocular using a total reflection mirror (for example, disclosed in Japanese utility model early laid-open publication No. Sho 58-62314). While a surgical operation microscope of this type does not require a brighter illuminating light source, a part of the observation field is vignetted by a total reflection mirror.
Another surgical operation microscope has a display element placed directly on an observing surface. In the surgical operation microscope of this type, however the display element must be sterilized because the display element is placed close to a diseased area. This sterilizing operation is troublesome, and the size and the configuration of the display element are limited.